From patchwork Tue Dec 5 16:39:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Filipe Manana X-Patchwork-Id: 13480419 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ABBA57ED; Tue, 5 Dec 2023 16:39:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="klmjZcJK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 516BAC433C7; Tue, 5 Dec 2023 16:39:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701794367; bh=aiDk4xrw2wvXGQzh51loxHNu4L7Wdhjc1iNbZ6sUlE0=; h=From:To:Cc:Subject:Date:From; b=klmjZcJKYmazo9dvRhAlDXVzTEsY8ENG/DmdM7dEMotUeN4IMcfqGdnrdXd6BGZ2q ciM6F3Evh6lGfDczEE8P983Drnyd4zFpxaENFwaG1OxChmKOuQorOHA1lJQ+15apFR P4bPr30LdYJW7eTtBZYomW2Seu+pZ8VmDUtcyiUZoLuiospN3HaVY1CznIhqo0qDA0 eHowzhR6NX5EnYDnuEvOukt5Z2VKXdf0Iz4ayxVQtn4MCMVZdmVYI7hFPqu5FUyzD+ HAi8wT7RiWeG8cIPJchI5X52HZSFJIA4fJ6rVI4BPrPfUFFm/FRnYl437YFKGyb0fd tda9mjwidoupQ== From: fdmanana@kernel.org To: fstests@vger.kernel.org Cc: linux-btrfs@vger.kernel.org, Filipe Manana Subject: [PATCH] generic: test reading a large directory while renaming its files Date: Tue, 5 Dec 2023 16:39:20 +0000 Message-Id: X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Filipe Manana Test that on a fairly large directory if we keep renaming files while holding the directory open and doing readdir(3) calls, we don't end up in an infinite loop. This exercise a bug that existed in btrfs and was fixed in kernel 6.5 by commit 9b378f6ad48c ("btrfs: fix infinite directory reads"). Signed-off-by: Filipe Manana Reviewed-by: Zorro Lang --- .gitignore | 1 + src/Makefile | 3 +- src/readdir-while-renames.c | 146 ++++++++++++++++++++++++++++++++++++ tests/generic/734 | 37 +++++++++ tests/generic/734.out | 2 + 5 files changed, 188 insertions(+), 1 deletion(-) create mode 100644 src/readdir-while-renames.c create mode 100755 tests/generic/734 create mode 100644 tests/generic/734.out diff --git a/.gitignore b/.gitignore index 4c32ac42..7508b6e8 100644 --- a/.gitignore +++ b/.gitignore @@ -121,6 +121,7 @@ tags /src/punch-alternating /src/pwrite_mmap_blocked /src/randholes +/src/readdir-while-renames /src/rename /src/renameat2 /src/resvtest diff --git a/src/Makefile b/src/Makefile index 8160a0e8..d79015ce 100644 --- a/src/Makefile +++ b/src/Makefile @@ -19,7 +19,8 @@ TARGETS = dirstress fill fill2 getpagesize holes lstat64 \ t_ofd_locks t_mmap_collision mmap-write-concurrent \ t_get_file_time t_create_short_dirs t_create_long_dirs t_enospc \ t_mmap_writev_overlap checkpoint_journal mmap-rw-fault allocstale \ - t_mmap_cow_memory_failure fake-dump-rootino dio-buf-fault rewinddir-test + t_mmap_cow_memory_failure fake-dump-rootino dio-buf-fault rewinddir-test \ + readdir-while-renames LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \ preallo_rw_pattern_writer ftrunc trunc fs_perms testx looptest \ diff --git a/src/readdir-while-renames.c b/src/readdir-while-renames.c new file mode 100644 index 00000000..afeefb04 --- /dev/null +++ b/src/readdir-while-renames.c @@ -0,0 +1,146 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2023 SUSE Linux Products GmbH. All Rights Reserved. + */ +#include +#include +#include +#include +#include +#include +#include + +/* Number of files we add to the test directory. */ +#define NUM_FILES 5000 + +int main(int argc, char *argv[]) +{ + struct dirent *entry; + DIR *dir = NULL; + char *dir_path = NULL; + int dentry_count = 0; + int ret = 0; + int i; + + if (argc != 2) { + fprintf(stderr, "Usage: %s \n", argv[0]); + ret = 1; + goto out; + } + + dir_path = malloc(strlen(argv[1]) + strlen("/testdir") + 1); + if (!dir_path) { + fprintf(stderr, "malloc failure\n"); + ret = ENOMEM; + goto out; + } + i = strlen(argv[1]); + memcpy(dir_path, argv[1], i); + memcpy(dir_path + i, "/testdir", strlen("/testdir")); + dir_path[i + strlen("/testdir")] = '\0'; + + ret = mkdir(dir_path, 0700); + if (ret == -1) { + fprintf(stderr, "Failed to create test directory: %d\n", errno); + ret = errno; + goto out; + } + + ret = chdir(dir_path); + if (ret == -1) { + fprintf(stderr, "Failed to chdir to the test directory: %d\n", errno); + ret = errno; + goto out; + } + + /* Now create all files inside the directory. */ + for (i = 1; i <= NUM_FILES; i++) { + char file_name[32]; + FILE *f; + + sprintf(file_name, "%s/%d", dir_path, i); + f = fopen(file_name, "w"); + if (f == NULL) { + fprintf(stderr, "Failed to create file number %d: %d\n", + i, errno); + ret = errno; + goto out; + } + fclose(f); + } + + dir = opendir(dir_path); + if (dir == NULL) { + fprintf(stderr, "Failed to open directory: %d\n", errno); + ret = errno; + goto out; + } + + /* + * readdir(3) returns NULL when it reaches the end of the directory or + * when an error happens, so reset errno to 0 to distinguish between + * both cases later. + */ + errno = 0; + while ((entry = readdir(dir)) != NULL) { + dentry_count++; + /* + * The actual number of dentries returned varies per filesystem + * implementation. On a 6.7-rc4 kernel, on x86_64 with default + * mkfs options, xfs returns 5031 dentries while ext4, f2fs and + * btrfs return 5002 (the 5000 files plus "." and ".."). These + * variations are fine and valid according to POSIX, as some of + * the renames may be visible or not while calling readdir(3). + * We only want to check we don't enter into an infinite loop, + * so let the maximum number of dentries be 3 * NUM_FILES, which + * is very reasonable. + */ + if (dentry_count > 3 * NUM_FILES) { + fprintf(stderr, + "Found too many directory entries (%d)\n", + dentry_count); + ret = 1; + goto out; + } + /* Can't rename "." and "..", skip them. */ + if (strcmp(entry->d_name, ".") == 0 || + strcmp(entry->d_name, "..") == 0) + continue; + ret = rename(entry->d_name, "TEMPFILE"); + if (ret == -1) { + fprintf(stderr, + "Failed to rename '%s' to TEMPFILE: %d\n", + entry->d_name, errno); + ret = errno; + goto out; + } + ret = rename("TEMPFILE", entry->d_name); + if (ret == -1) { + fprintf(stderr, + "Failed to rename TEMPFILE to '%s': %d\n", + entry->d_name, errno); + ret = errno; + goto out; + } + } + + if (errno) { + fprintf(stderr, "Failed to read directory: %d\n", errno); + ret = errno; + goto out; + } + + /* It should return at least NUM_FILES entries +2 (for "." and ".."). */ + if (dentry_count < NUM_FILES + 2) { + fprintf(stderr, + "Found less directory entries than expected (%d but expected %d)\n", + dentry_count, NUM_FILES + 2); + ret = 2; + } +out: + free(dir_path); + if (dir != NULL) + closedir(dir); + + return ret; +} diff --git a/tests/generic/734 b/tests/generic/734 new file mode 100755 index 00000000..ea3dfb2d --- /dev/null +++ b/tests/generic/734 @@ -0,0 +1,37 @@ +#! /bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Copyright (C) 2023 SUSE Linux Products GmbH. All Rights Reserved. +# +# FS QA Test 734 +# +# Test that on a fairly large directory if we keep renaming files while holding +# the directory open and doing readdir(3) calls, we don't end up in an infinite +# loop. +# +. ./common/preamble +_begin_fstest auto quick dir + +_cleanup() +{ + cd / + rm -fr $tmp.* + rm -fr $target_dir +} + +_supported_fs generic +_require_test +_require_test_program readdir-while-renames + +[ $FSTYP == "btrfs" ] && _fixed_by_kernel_commit 9b378f6ad48c \ + "btrfs: fix infinite directory reads" + +target_dir="$TEST_DIR/test-$seq" +rm -fr $target_dir +mkdir $target_dir + +$here/src/readdir-while-renames $target_dir + +# success, all done +echo "Silence is golden" +status=0 +exit diff --git a/tests/generic/734.out b/tests/generic/734.out new file mode 100644 index 00000000..4299839b --- /dev/null +++ b/tests/generic/734.out @@ -0,0 +1,2 @@ +QA output created by 734 +Silence is golden